add benchmark for root model validation (pydantic#1581)

Author: davidhewitt

tests/benchmarks/complete_schema.py

@@ -340,3 +340,22 @@ def input_data_wrong():
         'field_functions_model': {'field_before': 1, 'field_after': 1, 'field_wrap': 1, 'field_plain': 1},
         'field_recursive': {'name': 'foo', 'sub_branch': {'name': 'bar', 'sub_branch': {}}},
     }
+
+
+def wrap_schema_in_root_model(schema: dict) -> dict:
+    class MyRootModel:
+        # __slots__ is not required, but it avoids __pydantic_fields_set__ falling into __dict__
+        __slots__ = '__dict__', '__pydantic_fields_set__', '__pydantic_extra__', '__pydantic_private__'
+
+    return {
+        'type': 'model',
+        'cls': MyRootModel,
+        'config': {},
+        'schema': {
+            'type': 'model-fields',
+            'fields': {
+                'root': {'type': 'model-field', 'schema': schema},
+            },
+        },
+        'root_model': True,
+    }

tests/benchmarks/test_complete_benchmark.py

@@ -11,7 +11,7 @@
 
 from pydantic_core import SchemaSerializer, SchemaValidator, ValidationError, validate_core_schema
 
-from .complete_schema import input_data_lax, input_data_strict, input_data_wrong, schema
+from .complete_schema import input_data_lax, input_data_strict, input_data_wrong, schema, wrap_schema_in_root_model
 
 
 def test_complete_valid():
@@ -99,6 +99,12 @@ def test_complete_core_strict(benchmark):
     benchmark(v.validate_python, input_data_strict())
 
 
+@pytest.mark.benchmark(group='complete')
+def test_complete_core_root(benchmark):
+    v = SchemaValidator(validate_core_schema(wrap_schema_in_root_model(schema())))
+    benchmark(v.validate_python, {'root': input_data_lax()})
+
+
 @pytest.mark.benchmark(group='complete-to-python')
 def test_complete_core_serializer_to_python(benchmark):
     core_schema = validate_core_schema(schema())
@@ -160,6 +166,13 @@ def test_complete_core_json(benchmark):
     benchmark(v.validate_json, json_data)
 
 
+@pytest.mark.benchmark(group='complete-json')
+def test_complete_core_root_json(benchmark):
+    v = SchemaValidator(validate_core_schema(wrap_schema_in_root_model(schema())))
+    json_data = json.dumps({'root': input_data_lax()}, default=default_json_encoder)
+    benchmark(v.validate_json, json_data)
+
+
 @pytest.mark.benchmark(group='build')
 def test_build_schema(benchmark):
     lax_schema = schema()